A recent Swedish study reveals that developing type 1 diabetes (T1D) in adulthood significantly raises the risk of cardiovascular disease (CVD) and death—challenging assumptions that a later diagnosis results in better long-term outcomes.
Using comprehensive national registry data, researchers tracked over 10,000 adults diagnosed with T1D between 2001 and 2020, comparing them to more than 500,000 individuals without diabetes. The findings indicate that individuals diagnosed with T1D after age 40 face no substantial prognostic advantage compared to those diagnosed earlier in life.
Higher Risks Despite Age of Onset
The research, led by Yuxia Wei, a postdoctoral fellow at Karolinska Institutet, underscored smoking, obesity, and poor blood glucose control as primary drivers of poor outcomes. Notably, older patients were less likely to utilize insulin pumps—devices known to aid in managing blood sugar levels effectively.
“Patients diagnosed later in life tend to use assistive devices less, which contributes to worse glucose control and increased risk,” Wei explained.
A Gap in Research for Adult-Onset T1D
Historically, T1D prognosis data has focused on childhood and adolescent diagnoses. Adult-onset T1D has been less studied, with most evidence derived from research on type 2 diabetes (T2D) or general population data. This gap leaves clinicians with limited information on how age of onset influences long-term health outcomes.
Wei’s team aimed to fill this void by examining all-cause mortality, specific causes of death, and the incidence of major adverse cardiovascular events (MACE) among adult-onset T1D patients. They analyzed data through June 2022, providing a robust follow-up period.
Key Findings: Increased Mortality and Cardiovascular Events
The study included 10,184 adult-onset T1D patients, alongside 375,523 T2D patients and 509,172 non-diabetic controls. Hazard ratios (HRs) were calculated for mortality and cardiovascular outcomes, adjusting for various risk factors, including smoking status, body mass index (BMI), hemoglobin A1c (HbA1c) levels, blood pressure, lipid profiles, kidney function, and albuminuria.
Results showed that individuals with T1D had a 71% higher risk of death from any cause (HR 1.71; 95% CI, 1.60–1.84) and a 30% higher risk of experiencing a major cardiovascular event (HR 1.30; 95% CI, 1.17–1.45) compared to controls. Alarmingly, deaths from diabetic coma or ketoacidosis were nearly seven times more likely in T1D patients than in those with T2D (HR 7.04; 95% CI, 4.54–10.9).
While those diagnosed with T1D after age 40 showed slightly lower rates of non-cardiovascular deaths and cancer-related mortality compared to T2D patients, their overall cardiovascular and mortality risks remained significantly elevated.
Modifiable Risk Factors Drive Mortality
The study pinpointed smoking and poor glucose control as leading contributors to excess mortality, accounting for 10.7% and 10.4% of deaths, respectively. Overweight and obesity were linked to nearly 20% of major cardiovascular events in T1D patients, followed by smoking (8.4%) and suboptimal HbA1c levels (8.8%).
Importantly, researchers identified a clear dose-response relationship: the more risk factors present, the greater the excess risk of death and cardiovascular complications.
Call for Targeted Prevention Strategies
Sofia Carlsson, senior author and associate professor at Karolinska Institutet, emphasized the urgent need for better prevention and management strategies.
“Our findings highlight that improving glucose control, preventing obesity, and discouraging smoking can drastically alter outcomes, even for those diagnosed at older ages,” Carlsson stated. “We hope this research draws attention to the unique challenges of managing T1D in adults.”
This large-scale study underscores the pressing need for targeted interventions in adult-onset T1D, aiming to reduce the burden of cardiovascular disease and mortality through proactive risk factor management.
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